I don't usually splash more than 6" so I think you'd be okay. The raised bar is out because most people like to have the single height large surface for laying things out, especially where the island replaces a kitchen table. It's also easier for kids, old folks, and others to sit at the lower counter height. That is, there are a lot of practical reasons why people do a single, counter height, surface, which propels the style. If you like your raised bar and backsplash for the sink, and you like the way it looks and functions, there's absolutely no reason to remove it!!

We did exactly what you described, including making the window larger. It opens up into the computer/rec room. Here is what we started out with:

and here is the same view after the redo

Here is the old view from the computer room into the kitchen:

and the new:

And one more view:

We, too, wondered if we were making the right decision -- and we LOVE it. It is so much handier than the raised bar. When we have a buffet I move the chairs from the peninsula to the pass-thru and the kids eat there. It really makes the kitchen look bigger. No problems with splashing, either.I think we have about 18 inches from the sink to the other side.

It's great for unloading groceries, too. I come in from the computer room and put the bags on the pass thru. Decreases the pathway and heavy loads!

Go for it!

Thank you for the responses and especially the pictures, rjr!!! I love what you've done. I floated the idea to DH this morning -- he has reservations about spilling something and it running all over the place. Of course I didn't mention that the coffeemaker is bound to overflow again, just like it's done in the past. But, the more I think about it, the more I like the idea. I still have some other things to think about, though. The bar area and sink are on one leg of a U. The other leg is a peninsula. There are two outlets and two switches in the raised bar. One of the switches will go away but I need at least one of the outlets if not both. I think I have more questions to ask the contractor!